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�DCI <br />enoineews <br />Ba���a <br />Everett <br />Spokane <br />Portland <br />San Diego <br />AusGn May 20, 20I1 <br />Getinet Alewab <br />T'EC Mechanical <br />Rcdmond, WA <br />- <br />- <br />- <br />Su6jec(: IIVAClnstallafion: 909 Business cenfer <br />909 SE Everett Ma1l Way <br />Everett, WA 98208 <br />Mr. Alewab, <br />m ��Gs—a�w <br />;; <br />R <br />i. <br />We were asked to review die existing roof swcwre tor the replacement of 1 existing units with an HP-1 = 740 <br />Ibs. The original unit weighed about 600 Ibs. We reviewed and anatyzed the condition for latcral and gravity <br />impacts and determined what retrofi�s (if any) that would be rcquired. Additionally we determined th� <br />curb/slecper attnchment [equiremenLs based on the lateral design forces. <br />Result: <br />The exisfing .:truc�ure is adequate ta supparf the (oads of die new units. The CL beams and purlins thnt fn�ms <br />rhe roof supparting experiences a ner gain of 50-7516s per 6eam/purlin with tAe turrent sleepers rhat distribute <br />:he weight over supporting roof -members. Funhermare ti.� impact an �he raoJs��uc�ure, typically a�e designed <br />wifh full load design laad as weU as for the additional point lo�ds (unit), are accepm6fe as the curreri� increase <br />in load of less thm� 5%. Addiiionalfy, with ihe assumption rhat fhe joo�print aJ�he uni�s x�ou(d not experienre a <br />snaw loading (LL) due to �he hcat you could disregard �he live load which for the surface area oflhe HP-1 is a� <br />(east SOC lbs. By doina this yau efimina(ed SOO lbs off the supporting mem6ers for the NP•!. By �easoning the <br />additional loading is less :ha� die live load wo�dd have 5een over the area as rhe roof is strucruralty sound <br />unless signs af deficiencies in 1he raof structu�e are presenr. <br />7he new uni�s will 6e installed in the same loca�ions as the a�iginal unirs and will be insml(ed on the existing <br />curblsleepers connected ta fhe roof structure. In terms of the attachmen� reguirements; use a minimum oJ(4) <br />sheet memi saews or wood screws (#l0) m eanc �urb atmchmendsfeeper, minimum (2) oJthe sides oJthe uni�. . <br />See attad7ed cafcufation patkage with g�avity and lateral calculafions inc6�ding sketches and ke��-plans. <br />Please call me if you have any funher questions. <br />Sincerely, <br />it an. 2'1 mrEell, P.E. <br />Project Managcr <br />DCI Engineers, Seattic <br />10900 NE 4th Street, SuAe 1200 Bellevue, Washington, 99004 Phorre (42� 827-2238 <br />S e r v i c e I n n o v a t i o n V a I u e <br />